Draft regulator for combustion apparatus



Dean 3, 194D. I... MQNNEY DRAFT REGULATOR FOR COMBUSTION APPARATUS FiledAug. 22, 195% Patented Dec. 3, 1940 DRAFT REGULATOR FOR COMBUSTIONAPPARATUS Louis Monney, Lausanne, Switzerland, assignor to the firmRecomatic a'firm'of Switzerland S A, Geneva, Switzerland,

Application August 22, 1938; Serial N 0. 226,162 In Switzerland August30, 1937 i 3 Claims. (Cl. 236.-96).

This inventionrelates tocombustion heating installations and inparticular to draft regulators for combustion apparatus of the typecomprising thermostatic means for controlling the admission of exteriorair through a lateral opening into the flue gas conduit of the furnace,regulating in consequence the combustion process by the dependentadmission of air under the grate.

It is an object of the invention to provide a thermostatic bladeextended within said flue, and members which kinematically connect saidblade with a shutter of said opening in th wall of the flue.

A further object of the invention is the provision of a device forvarying the relative position of said blade and said shutter by manuallyoperated means situated outside the flue.

In the drawing:

Fig. 1 is a vertical sectional detail of one form of the invention,

Fig. 2 is a similar view of another form of the invention,

Fig. 3 is a vertical sectional detail partly in elevation of a furthermodification,

Fig. 4 is a fragmentary sectional el-evational detail looking toward theright hand side of Figure 3.

In Figure 1 a flue gas conduit or chimney l of a furnace, notillustrated, is provided with an opening, which is closed up by a frameconstituted by a plate [2 with an opening provided therein. On thisframe is fixed an arm 3 which is extended into the interior of the flueI and carries the hinge of a lever 2 which, in combination with abimetallic blade 4 and a connecting rod 5, constitute a device forcontrolling the draft of the flue gas in the chimney. The blade 4 is atone end fixed to the lever 2 and at the other end rotatably connected tothe rod 5, which couples the blade with a shutter 6 mounted rotatably onan axle 1 which crosses the opening from one border of the plate [2 tothe other, the shutter being disposed in a way that it can close theopening of the plate l2. The axles of the hinges of the connecting rod 5on the blade 4 and on the shutter 6 are parallel to the axis 1. Theweight of the rod 5 and of the blade 4 acts to tip the lever 2, which,however, rests with its free end against a cam ll fixed to the end of ashaft 9 rotatable in a tube 8 carried by the plate l2 and extended intothe interior of the flue. The end of the shaft 9 projects beyond theplate at the exterior side and has an operating button It! thereon and apointer 9a,

the temperature of the flue gas.

the position of which can be marked by a scale, not illustrated, on theplate l2.

' It will be understood that the button facilitates the turning of thecam H which determinesthe apertureangle of the shutter for a certaincurvature of the blade 4, depending on The aperture is therefordetermined for every temperature higher than that for which the shuttercloses the opening completely, if the device is adjusted so that theclosing is possible; not that it is necessary in every case, as apermanent draft of air can be desirable, when the temperature is low.

The blade bends freely towards the right hand side when heated, thusopening the shutter. In order to close the opening between twodetermined limits of temperature the borders of the opening are providedwith extended edges.

In Figure 2 the lever 2.1 of the thermostat is shaped and mounted in away that one arm is arranged through a slot l3 in the plate I2, andrests against a cam a mounted on the exterior side of the plate. Thiscam has a pointer l4 and a handle l5.

In Figure 3 one arm of the lever 2b of the 25 thermostat is prolongatedto the exterior side of the chimney and terminates in a forked arm witha slot 16 in each arm. A bolt ll fixed to one end of a vertical shank I8is engaged in those two slots it; the shank passing through a support 20fixed to the plate l2 and carrying at its other, screw-threaded end anoperating nut 2| and between the support 20 and the lever 2b a springI9. The nut 2| facilitates the regulation of the position of thethermostat relative to the fixed parts of the apparatus, with the sameresults as described under Fig. 1 and 2.

If the shutter when closing is met by a stop, the blade bending to theleft hand side tries to tip the lever 2b in clockwise direction andconsequently to compress the spring I 9, whereby the spring is weakenough that the blade will support the resulting strain without beingdamaged.

It must be noticed that the strains supported by the blade 4 are verylittle because the shutter 6 is practically in indifferent equilibriumon its axle and it is mounted in a manner that it follows every movementof the free end of the blade 4.

Iclaim:

1. In combination with the flue of a combus tion apparatus, having alateral air inlet opening and an aperture and a damper adapted to closesaid opening, a thermostatic blade disposed within the flue, memberskinematically connecting one end of the thermostaticblade with thedamper, a bracket fixed inside the flue, a lever extending transverselywithin the flue and pivotally mounted on the bracket, one end of saidlever being secured to the other end of the thermostatic blade while theother end of said lever extends through the aperture, an adjustingdevice outside the flue cooperating with the projecting end of the saidlever for varying the relative positions of the blade and the damperwith respect to each other, and means outside the flue for operatingsaid device.

2. In combination with the flue of a combustion apparatus, having alateral air inlet opening and an aperture and a damper adapted to closesaid opening, a thermostatic blade disposed within the flue, memberskinematically connecting, one end of the thermostatic blade with thedamper, a lever extending transversely within the flue and pivotallymounted on the inside of the flue wall, one end of said lever beingsecured to the other end of the thermostatic blade while the other endof said lever extends through the aperture, a cam disposed outside thefiue and rotatably mounted on the flue wall, said cam being adapted tocooperate with the projecting end of said lever for varying the relativepositions of the blade and the damper with respect to each other, and ahandle on said cam for manually operating the same.

3. In combination with the flue of a combustion apparatus, having alateral air inlet opening and an aperture and a damper adapted to closesaid opening, a thermostatic blade disposed within theflue, memberskinematically connecting one end of the thermostatic blade with the damper, a lever extending transversely within the flue and pivotally mountedon the inside of the flue wall, one end of said lever being secured tothe other end of the thermostatic blade while the other end of saidlever extends through the aperture and is in. the. shape of a forkhaving a slot in each of its prongs, a support fixed to the outside ofthe" flue wall, a screw threaded shank passing said support and slidabletherein, a pin rigid with one end of said shank and engaging the slotsin the fork-shaped end of the lever, an operating nut seated on theother end of said shank and bearing against said support, and a springon said shank, bearing on the one side against the support and ontheother side against a fork-shaped end of the lever, so as to turn saidlever against the spring action when exerting a traction on said shankby means" of said operating nut.

LOUIS MONNEY.

